三角褐指藻对铜离子长期暴露的生理响应

探讨了不同浓度Cu2+长期暴露对三角褐指藻生长、光合作用、呼吸作用和色素含量等生理特性的影响。结果表明:三角褐指藻在较低浓度下(0.25mg·L-1,0.5mg·L-1)生长受到刺激,而在高浓度下(1.5mg·L-1)则下降。叶绿素荧光参数有效光化学效率(Yield)与最大光化学效率(Fv/Fm)对Cu2+非常敏感,它们均随Cu2+的升高而显著下降;Cu2+暴露对光合作用速率也具有抑制作用;而在Cu2+长期暴露下,类胡萝卜素含量比对照组高,但提高的程度随Cu2+浓度升高而下降。这些结果说明,叶绿素荧光参数可以作为三角褐指藻受到Cu2+胁迫的灵敏指标;光合作用与生长并不耦合;类胡萝卜素含量和呼吸作用速率升高可能能够降低Cu2+对三角褐指藻的毒性。

Physiological responses of Phaeodactylum triconutum to long-term copper (Ⅱ) exposure

This paper investigates the effect of the long-term exposure of different concentrations of copper (Ⅱ) on growth, photosynthesis, respiration and contents of pigments in the diatom Phaeodactylum triconutum. The results showed that the growth rates were stimulated under low concentration of Cu~(2+) (0.25-0.5mg·L~(-1)) , but were depressed under high concentration of Cu~(2+) (1.5mg·L~(-1)) . Both effective quantum efficiency (Yield) and the optimal quantum yield (Fv/Fm) were sensitive to Cu~(2+), being markedly reduced with the increase of Cu~(2+) concentration. Photosynthetic rates were also inhibited with the exposure to Cu~(2+). However, the contents of carotenoid of the alga exposed to Cu~(2+) were higher than the control, but the contents decreased while concentrations of Cu~(2+) increased. It is proposed that chlorophyll fluorescence parameters can be a sensitive indication for Cu~(2+) stress. Photosynthesis is not coupled with the growth. The increase of contents of carotenoids and the rates of respiration may protect Phaeodactylum triconutum from the toxicity of copper.